Heat controlled gas lift valve

ABSTRACT

A gas lift valve having a seat and a valve element for admitting pressurized fluid into a well conduit in which the operation of the valve is controlled by heat. A closed chamber having a fluid therein which is exposed to the valve element for moving the element in one direction as the fluid expands, said fluid being expandable and the pressure increases when heat is applied thereto, and the fluid pressure decreases on removal of heat therefrom. Means for applying and/or removing heat from the closed chamber for controlling the actuation of the valve. An electrical or fluid heating coil positioned adjacent the closed chamber and a control line leading to the well surface for controlling the heat applied to the closed chamber. A cooling coil positioned adjacent the closed chamber with a control line leading to the surface for controlling the heat removed from the closed chamber.

United States Patent 1191 1111 3,760,832 McGowen, Jr. et al. I Sept. 25, 1973 HEAT CONTROLLED GAS LIFT VALVE Primary I'. \'um1'm'rAlan Cohan [75] Inventors: Harold E. McGowen, Jr.; Gilbert H. AImmEyTJameS et Tausch, Houston, Tex.

[73] Assignee: Camco Cincorporated, Houston, [57] ABSTRACT Tex, A gas lift valve having a seat and a valve element for ad- [22] Flled: 1971 mitting pressurized fluid into a well conduit in which [21] APPL No: 197,828 the operation of the valve is controlled by heat. A

closed chamber having a fluid therein which is exposed to the valve element for moving the element in one dil, rection as the expands said being expand- [51] Int. Cl. F041 1/08 able and the pressure incl-eases when heat is applied [58] Field of Search 137/155; 251/1 1; thereto, and the fl id pressure decreases on removal f 417/1 12 heat therefrom. Means for applying and/or removing heat from the closed chamber for controlling the actual References Clled tion of the valve. An electrical or fluid heating coil po- UNITED STATES PATENTS sitioned adjacent the closed chamber and a control line 2,044,427 6/1936 Giesler 251/11 x leading 10 the Surface for Controlling the heat p- 3 414 231 12/19 Kramer N 251/11 plied to the closed chamber. A cooling coil positioned 2,759,429 8/1956 Bubb 137/155 X adjacent the closed chamber with a controlline leading 2,914,078 11/1959 McGowen 137/155 to the urface for controlling the heat removed from the closed chamber.

8 Claims, 4 Drawing Figures VAR/A BL E PATENTED SEPZS I975 VAR/ABA E MEANS PATENTED SEPZSIHB BACKGROUND OF THE INVENTION Generally, it is old to provide a subsurface gas lift valve located in a well bore and connected to a well tubing for injecting pressurized gas from outside the well conduit to inside the well conduit to provide a gas lift for fluid in the well conduit. Generally, gas lift valves are pressure operated in which a fixed closing force is obtained from a pressure charged bellows and the valve is controlled by the injection gas pressure.

The present invention is directed to improvements in a gas lift valve in which the valve opening and/or closing, as well as the degree of opening, can be controlled by providing a heat controlled well safety valve which can be operated and controlled from the well surface.

SUMMARY The present invention is directed to a heat controlled subsurface gas lift valve connected to a well conduit which may be controlled by the application and/or removal of heat.

A further object of the present invention is the provision of a heat controlled gas lift valve having a seat and valve element for admitting pressurized fluid into a well conduit by providing a closed chamber having a fluid therein which is exposed to the valve element for moving the valve element in one direction as the fluid expands. The fluid is expandable when heat is applied thereto and contractable when cooled and means are provided for controlling the heat of the closed chamber thereby controlling the actuation of the valve.

Yet a still further object of the present invention is the provision of control means for controlling the heat of a heat actuated gas lift valve which is variable thereby controlling the valve opening and closing and the degree of opening.

Still a further object of the present invention is the provision of a bellows operated gas lift valve by providing a closed chamber having a fluid therein which is exposed to the bellows for moving the valve in one direction and means for controlling the heat of the fluid thereby controlling the actuation of the valve, and said heat control means extends the well surface.

Yet a further object of the present invention is the provision of controlling a heat actuated gas lift valve in which the controlling means is an electrical or fluid heating coil adapted to be positioned adjacent the closed fluid chamber.

Yet a further object of the present invention is wherein the control means for a heat controlled gas lift valve is a cooling jacket positioned adjacent the closed fluid chamber.

A still further object of the present invention is the provision of a retrievable gas lift valve actuated by heat in which a heating coil is positioned in the well conduit adjacent the seated position of the valve and a control line extends to the well surface for controlling the amount of heat applied to the valve.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a fragmentary elevational view, partly in cross section, illustrating a heat operated gas lift valve of the present invention of the nonretrievable type,

FIG. 2 is a fragmentary elevational view, partly in cross section, illustrating a retrievable type gas lift valve mounted in the sidepocket of a mandrel,

FIG. 3 is a schematic elevational view of an embodi ment of a gas lift valve which closes on reduction of heat, and

FIG. 4 is a schematic elevational view of a heat controlled gas lift valve which is controlled by a fluid control line.

DESCRIPTION OF THE PREFERRED EMBODIMENT While the present improvement in a subsurface gas lift valve will be shown, for purposes of illustration only, as incorporated in a bellows type valve, it will be understood that the present heat controlled gas lift invention may be used in other types of gas lift valves.

Referring now to the drawings, and particularly to FIG. 1, one type of gas lift valve is shown utilizing the present invention, and generally indicated by the reference numeral 10. The valve 10, as shown in FIG. 1, is of a nonretrievable type gas lift valve which is mounted on the side ofa well tubing 12 such as by threaded connection 14. The valve 10 generally includes a valve seat 16 and a valve element 18 for controlling the flow of a pressurized injection fluid from outside of the tubing 12 through ports 20 and into passageway 22 leading t the interior of the well conduit 12. e

As is conventional, a bellows 24 is connected to the valve element 18 and subjected to pressure in a closed chamber 26. In the embodiment shown in FIG. 1, the pressure in the closed chamber26 acts over the effective area of the bellows 24 to seat the valve element 18 on the valve seat 16 thereby closing the gas lift valve. The valve is opened by the injection of pressurized gas which flows through the ports 20 and acts against the effective area of the bellows less the area of the valve seat 16 although the opening force is assisted by the tubing pressure in the well tubing 12 acting through the passageway 22 against the bottom of the valve element 18. Of course, the pressure in the chamber 26 in a conventional gas lift valve is fixed and cannot be varied to control the closing or opening force or the degree of opening the valve.

The present invention is directed to providing an improved gas lift valve which is heat controlled. Thus, the present invention is directed to providing a fluid 28 in the chamber 26, either liquid or gas, which expands or vaporizes as the temperature in the chamber 26 is increased thereby increasing the fluid pressure in the chamber. Similarly, the fluid 28 will contract and lower its pressure on removal of heat. While any suitable fluid such as hydrocarbons may be used, refrigerants such as halogenated hydrocarbons such as sold under the trademark Freon are preferred because of their higher pressure upon vaporization and their safety and availability although other fluids such as carbontetrachloride may be used. Thus, as heat is applied to the chamber 26, the pressure of the fluid 28 is increased to provide a greater closing force against the bellows 24 and the valve element 18 to cause the valve element 18 to seat more firmly on the valve seat 16 require a thus to requirea greater opening force. And conversely, when heat is removed from the chamber 26, the fluid 28 therein will cool and the pressure will decrease thereby decreasing the closing pressure of the bellows 24 seating the element 18 on the seat 16. And, of course, by varying the amount of heat applied to the fluid 28, the amount of closing force which the closed chamber 26 exerts on the bellows 24 and the valve can be varied to meet changing well conditions.

Any suitable heating means may be used to apply heat to the closed fluid chamber 26 such as steam conduit. However, the preferred form of the heating means is by the use of a heating coil 30 preferably built in the housing of the valve and surrounding the chamber 26. The coil 30 may be electrically energized by a single electrical conductor 40 with the tubing 12 used as the other electrical conductor thereby requiring only a single insulated conductor 40 leading to the well surface. The application of heat may be initiated, stopped, or varied by a suitable variable voltage means 42 located at the well surface. Therefore, the amount of heat applied to the fluid 28 in the chamber 26 can be varied by varying the variable voltage means 42. Thus, the pressure in the chamber 26 may be increased or decreased to control the closing and opening of the valve element 18 on the seat 16 as well as controlling the degree of opening.

Of course, other and further embodiments and modifications may be made, such as shown in FIGS. 2, 3 and 4, where like parts to those shown in FIG. 1 are given corresponding numbers with the addition of a suffix a, b, and c, respectively.

The heat controlled gas lift valve 10a shown in FIG. 2 is of a retrievable type such as one that can be seated in a sidepocket 34 of a mandrel 36 which is installed in a well conduit. Thus, the fluid 28a which is expandable when heat is applied thereto acts against the bellows 24a to provide a force for closing the valve element 18a on the valve seat 16a. Ports 38 are provided in the sidepocket 34 in communication with the valve ports a to admit injection pressurized fluid when the valve 10a is opened to flow through passageway 39 and into the interior of the mandrel 36 and well tubing. Preferably, the heating coil a is positioned in the mandrel 36 so as to be adjacent the closed chamber 26a when the valve 10a is seated in the sidepocket 34. As in FIG. 1, a single electrical conductor 40a may be used to provide the electrical energy to the heating coil 30a for controlling the actuation of the valve 10a. In addition, the single electrical conductor 40a may be utilized to control an additional gas lift valve through electrical line 44 by placing a first diode 46 connected to the coil 30a and a second diodd 48 in a reverse position in line 44 to a second gas lift valve. Thus, a switch 50 may be alternately energized to control the transmission of electrical energy to line 40a and through either diode 46 or 48 to control the amount of heat and thus the actuation of two gas lift valves.

The embodiments of FIGS. 1 and 2 illustrate gas lift valves in which heat is applied thereto in a manner that an increased application of heat closes the valve. The embodiment shown in FIG. 3 illustrates a heat controlled gas lift valve of the present invention in which an increase of heat to the closed fluid chamber acts in a direction to open the valve. Thus, in FIG. 3 the bellows 24b is connected to the closed chamber 26b such that an increase in pressurein the fluid 28b acts in a direction to unseat the valve element 18b off of the seat 16b. If desired, a spring 52may be provided to provide an additional closing force. By increasing the electrical voltage transmitted over line 40b to the electrical coil 30b the temperature of the fluid 28b is increased in a direction to provide an opening force on the valve 10b or to decrease the opening force required by the injection fluid. Of course, by decresing the electrical energy transmitted to the coil 30b the amount of heat applied to the closed chamber 26b will be decreased thereby decreasing the opening force of the bellows 24b.

Referring now to another embodiment as best seen in FIG. 4, the means for controlling the heat of the closed chamber 26c and the fluid 28c therein is a fluid conduit coil extending to the well surface. In one use, steam may be supplied from the well surface through the conduit coil 60 to apply heat to the fluid 28c and against the bellows 240 in a direction to seat the valve element on the valve element 16c to provide a closing force acting to close the valve 100.

However, the embodiment of FIG. 4 may also be used for removing heat from the closed chamber 26c to decrease the pressure of the fluid 28c therein. As is well known, the temperature in a well bore at a sufficient depth may be sufficiently great in some environments to provide sufficient heat to the fluid 280 in the closed chamber 260 to provide the desired closing force on the valve 100. Under such conditions, means may be provided for removal of heat from the closed chamber 26c for controlling the operation of the 'valve 10c. In that event, the fluid conduit 60 may be supplied with a cooling fluid, such as cooling water from the well surface, to control the amount of heat applied to the fluid 28c and thus control the operation of the valve 10c. Of course, when the flow of cooling fluid through the conduit coil 60 is stopped, the natural heat in the well bore will then be applied to the fluid 28c to increase thepressure and the closing force therein.

The present invention, therefore, is well adaptedto carry out the objects and attain the ends and advantages mentioned as well as other inherent therein. While presently preferred embodiment of the invention are given for the purpose of disclosure, numerous changes in the details of construction and arrangement of parts will readily suggest themselves to those skilled in the art and are encompassed within the spirit of the invention and the scope of the appended claims.

What is claimed is: 9

l. A heat controlled gas lift valve for admitting pressurized fluid into a well conduit comprising,

a well mandrel for connection to a well conduit in a well below the well surface, said mandrel including a passageway extending between the interior and the exterior of the mandrel,

a gas lift valve having a seat and a valve element secured to the mandrel for controlling the opening and closing of the mandrel passageway, said element exposed to pressure exteriorly of the mandrel acting to move said element to an open position,

a closed chamber in the valve having a fluid therein which is exposed to the valve element for moving the element in one direction as the fluid expands, said'fluid being expandable when heat is applied thereto, and

coil means positioned adjacent the closed chamber and extending to the well surface for controlling the heat of the closed chamber thereby controlling the actuation of the valve.

2. The apparatus of claim 1 wherein the heat of the coil means is variable.

3. The apparatus of claim 1 wherein the coil means includes a cooling jacket positioned adjacent the closed chamber.

4. The apparatus of claim 1 wherein the coil means includes a fluid heating jacket positioned adjacent the closed chamber 5. The apparatus of claim 1 wherein the coil is an electrical heating coil positioned about the closed chamber.

6. The apparatus of claim 1 wherein the fluid is a halogenated hydrocarbon.

7. The apparatus of claim 1 wherein the mandrel includes an offset internal sidepocket receiving the valve and the coil is positioned in the mandrel about the closed chamber.

8. A heat controlled gas lift valve for admitting pressurized fluid into a well conduit comprising,

a well mandrel for connection to a well conduit in a well below the well surface, said mandrel including a sidepocket having a fluid passageway extending between the interior and the exterior of the mandrel,

a gas lift valve positioned in the side-pocket and having a seat and valve element for opening and closing the fluid passageway, said element exposed to pressure exteriorly of the mandrel acting to move said element to an open position,

a closed chamber in the valve having a pressurized fluid therein which is exposed to the valve element for moving the elementin one direction as the fluid expands, said fluid being expandable when heat is appliedthereto,

an electrical heating coil positioned in the internal sidepocket and about the closed chamber and leading to the well surface for controlling the heat applied to the fluid in the closed chamber thereby controlling the actuation of the valve. 

1. A heat controlled gas lift valve for admitting pressurized fluid into a well conduit comprising, a well mandrel for connection to a well conduit in a well below the well surface, said mandrel including a passageway extending between the interior and the exterior of the mandrel, a gas lift valve having a seat and a valve element secured to the mandrel for controlling the opening and closing of the mandrel passageway, said element exposed to pressure exteriorly of the mandrel acting to move said element to an open position, a closed chamber in the valve having a fluid therein which is exposed to the valve element for moving the element in one direction as the fluid expands, said fluid being expandable when heat is applied thereto, and coil means positioned adjacent the closed chamber and extending to the well surface for controlling the heat of the closed chamber thereby controlling the actuation of the valve.
 2. The apparatus of claim 1 wherein the heat of the coil means is variable.
 3. The apparatus of claim 1 wherein the coil means includes a cooling jacket positioned adjacent the closed chamber.
 4. The apparatus of claim 1 wherein the coil means includes a fluid heating jacket positioned adjacent the closed chamber.
 5. The apparatus of claim 1 wherein the coil is an electrical heating coil positioned about the closed chamber.
 6. The apparatus of claim 1 wherein the fluid is a halogenated hydrocarbon.
 7. The apparatus of claim 1 wherein the mandrel includes an offset internal sidepocket receiving the valve and the coil is positioned in the mandrel about the closed chamber.
 8. A heat controlled gas lift valve for admitting pressurized fluid into a well conduit comprising, a well mandrel for connection to a well conduit in a well below the well surface, said mandrel including a sidepocket having a fluid passageway extending between the interior and the exterior of the mandrel, a gas lift valve positioned in the side-pockeT and having a seat and valve element for opening and closing the fluid passageway, said element exposed to pressure exteriorly of the mandrel acting to move said element to an open position, a closed chamber in the valve having a pressurized fluid therein which is exposed to the valve element for moving the elementin one direction as the fluid expands, said fluid being expandable when heat is appliedthereto, an electrical heating coil positioned in the internal sidepocket and about the closed chamber and leading to the well surface for controlling the heat applied to the fluid in the closed chamber thereby controlling the actuation of the valve. 